Electrolyte level indicator



April 10, 1934.

5. c. VAIL El AL ELECTROLYTE LEVEL INDICATOR Filed Feb. 7, 1931 WW, W

Patented Apr. 10, 1934 1,954,435 ELECTROLYTE LEvEL INDICATOR.

Samuel C. Vail, Evanston, and Arthur B. Cunningham, Chicago, 111.

Application February 7, 1931, Serial No. 514,158 1 Claim. (01. 136-182)The present invention relates to indicating devices, more particularlyto a liquid level indicating device for storage batteries andcomprehends means for giving an indication when the level of theelectrolyte of the cell or cells of the battery falls below apredetermined minimum level beyond which it is unsafe to continue theuse of the battery.

One object of the invention is to provide an electrolytic levelindicator which is simple in construction, inexpensive to install, anddependable and eillcient in operation.

Another object of the invention is to provide an electrical signalsystem which may be readily applied to batteries already in service withonly slight modification of the batteries and which does not impair theefflciency of the battery.

A further object of the invention is to, provide a signalling system forinstallation on automolo biles for indicating to the operator of theautomobile or other vehicle when the electrolyte in the cell or cells ofthe battery has been used to or beyond a predetermined low level.

A still further object of the invention is to provide a system whereinan electrode is placed in each cell of the battery and connected to asignalling device located at a convenient point remote from the batteryand which is energized by the closing of the circuit between thesignalling device and a pair of the electrodes.

The system further comprises a normally open circuit which may be closedat will to give an indication of the condition of the individual cells 5or the battery and in which no element is introduced into the cellswhich induces any chemical action or produces any substance which has aninjurious eifect upon the battery.

with these and other objects in view, the invention consists of certainnovel features of construction and operation as will be more fullydescribed and particularly pointed out in the speciflcation, drawing,and claim appended hereto.

In the drawing, wherein like reference characters are used to designatelike parts,

Fig. 1 illustrates the preferred form of the invention as applied to athree cell storage battery,-

which is in section, with the plates removed.

Fig. 2 is a side elevation of a battery with a modified form of theinvention applied thereto. Fig. 3 is a view similar to Fig.2 showing amodification of the invention.

Fig. 4 shows a modification of' the invention illustrated in Fig. 3.Fig. 5 is a side elevation of a storage battery with a modified form ofthe invention applied thereto.

Fig. 6 is a side elevation of the contact device, filler opening cap andconnector terminal clip.

While several embodiments of the invention have been illustrated, it isto be understood, however, that the invention is not limited to anyparticular type or any specific use as modifications and uses within thescope of the invention readily suggest themselves to those skilled inthe art and it is obvious, therefore, that the invention may be utilizedto indicate the condition of the electrolyte in storage batterieswherever used, regardless of the purpose for which they are used.Furthermore, the indication may be and is intended to be given at aconvenient location where it may be readily observed regardless of thelocation of the battery itself.

Referring to the exemplary embodiment of the invention illustrated inFig. l, the battery container or box & comprises cells 1, 2, and 3,which may be of any well known construction. Each of the cells containsthe usual positive and negative plates which, for purposes ofillustration, have been omitted from the drawing to more clearlyillustrate the invention, the terminal of a positive plate assembly 5and the terminal of a negative plate assembly 6. These assemblies areconnected thru connectors 'l and 8 as is well known in the art.Intermediate electrodes 9, 10, and 11 project into the batterypreferably, though not necessarily, thru the closure caps 12, 13, and 14respectively. These electrodes extend into the cells a short distancebelow the normal level of the electrolyte, which level is indicated bythe eight of the liquid illustrated in the cell.

The conductor 15 connected with the electrode 9 branches into twobranches which terminate in the switch contacts 16 and 17. The otherconductor 18 connected with the electrode 10 also branches into twobranches which terminate in the switch contacts 19 and 20. Likewise, athird conductor 21 connected with the electrode 11 also branches intotwo branches which terminate in the switch contacts 22and 23. A doublepole switch 24 provided with contact engaging arms *25 and 26, adaptedto cooperate with the aforementioned contacts, is connected to theindicator 2'! thru conductors 28 and 29.

The switch 24 may be incorporated in the casing with the instrument 29or it may be located at a point remote from said indicator. This switchis preferably maintained in open position by means, such as a spring, sothat the indicator circuit is at all times open since it is unnecessaryfor acontinuous indication, it being suffiand 11 isv approximately oneand a half volts. cient to manually operate the switch when an Thisvoltage, of course, depends upon the state indication is desired. Theswitch may also have of the charge of the battery, the individual cells,a. pointer cooperating with indicia corresponding and the conditionsunder which it is operating. 5 to the number of cells of the battery.According to these voltages, the indicator needle. 8f

When it is desired to test the battery to see when connected acrosselectrodes '9 and 10, will if the electrolyte O be ow a predetermineddeflect a certain distance and will deflect sublevel, the switch 24 isturned one St p to the stantially the same distance upon connection i ha viewed in Fi 1. This movem n f across the electrodes and 11, while thedeflec- 10 the Switch b ngs the arms 25 and 26 thereof into tion will begreater when the instrument is con- 8 cooperation with the contacts 16and closing t d across th l t od 9 d 11, the circuit between theelectrodes 9 and 10. If The indicator 27 may be either of the direct orthe electrolyte in the cells 1 and 2, in which the alternating currenttype, preferably a, milliaml ctrodes 9 and 0 a p is above a D meter,designed to operate on very small current.

15 termined normal leve the indicator needle Will In the use of thedirect current type of indicator, 9O

deflect from Zero position, thereby indicating be necessary however tohave the indjthat the electrolyte in these cells is above its nortproperly connected so t t t polarity of mal level. the pairs of theelectrodes will be in the same di Further rotation of the Switch to theright rection. This precaution, however, is not necesbrings the contactarms and 26 Of the switch a -y in the alternating current type ofinstruiIItO cooperation the Contacts and 22, ment preferably though notnecessarily thereby closing the circuit across the electrodes has theZero position of the needle at the 10 and 11 and as before if the levelof the elecpoint of the scale. If the zero Eat the midpoint, tlclytc inthe cells 2 and 3 is above h lower one polarity would cause the needleto deflect in ends of the electrodes 9 and 101 the mdlcator onedirection while the opposite polarity would needle will again deflectthereby indicating that cause the needle to defle t in the oppositedirec there is sufficient electrolyte in these cells. Furtion f om itsmidposition' Instead of an indi ther rotation of the Switch to the htbrlllgs catoralight may be used to indicate, by illuminathe Contact arms25 and 26 mto coopffratlon w1 th tion thereof, when the electrolyte isabove its pre- 30 the Contacts 17 and 23 thereby closmg e determinedvalue. The light, however, being cuit across the electrodes 9 and 11 and1f the made to Conform to the voltages of the circuit electrolyte incell 3 is above its normal value, the Operates in a ti f t mannerindicator needle will again deflect thereby indi- The term must beconsidered E that h level of the electrolyt? is wherever used herein asa broad, comprehensive 35 Its pl'edetermmed low level lfrrovldecl wllfhterm intended to include any responsive element a spring upon release ofthe w t Wm which may be operated by the current across the be moved toits normal open position illustrated electrodea in In the modificationillustrated in Fig. 2, the

From the foregoing, it will be seen that by this parts are numbered thesame as those in Fig. 1,

40 arrangement, the level of the electrolyte in the but have theexponent s added thereto In individual cells of the battery may betested and, this arrangement the conductor 29 Connected to as before, ifthis level is above the predetermined the electrode branches into twobranches low point beyond which it is undesirable to which terminate inswitch contacts 30 and 31. eFate the battery because of q l theljeto Theconductor 32 connected to the electrode 10" 45 t of such low level W111terminates in the switch contact 33 and likewise an Indication of suchcondltmn' However 1f the conductor 34 connected with the electrode theelectrolyte is low in one of the cells, for exterminates in a switchContact The ample cell when the Switch is first shifted dicator 27* isconnected by conductors 28 and the indicator needle will not deflectbecause the to the switch provided with Contact arms 50' circuit thmughthe electmlyte is broken on 25 and 26% When it is desired to test thebatcount of non-contajct with h electrode tery the switch is turned tothe right as viewed From this indicatlon alone It W111 not he in Fig. 2,thereby closing the circuit across the slble to determine which of thecells 1 or 2 9" contacts 30 and 33 and if the electrolyte in the quiresh addltion of .electrolyte however cells with which these electrodes areconnected 55 upon shlftmg of the swltch to D051 is above itspredetermined value, the indicator tion the indicator operatesit wln1ndicte that needle will deflect. Further rotation of the switch P 1requires t t Ifjnstefm of mdlcat' closes the circuit across the contacts33 and 35 when the shiftfed Second and if the level of the electrolytein the cells sition there is no indication, it will still be doubtwithwhich these contacts are associated is above 60 as to which of the cells2 or 3 electrolyte its predetermined value, there will be an indicaisbelow its predetermined low point. However. tion by the needle if uponShifting of the switch to its third P Further rotation of the switchcloses the cirtion and closing the circuit across the electrodes cui'tacross the contacts 35 and 31 which are com 9 and 11 there is anindication, s wcllld indi" nected by their respective conductors to theeleces Cate that the electrolyte of the cell 2 1s below trodes 9 and 11and if the level of the electrot predetermined low value a therefore,lyte is above its predetermined point in these quir fill n n h r w rindlcatol cells, an indication will also be given by the inoperatesacross at least two'cells at a time and dex. If, however, there is noindication across by the ar a g me t d s d 111 1t 15 P any two of theswitch contacts the particular cell 70 Slblc to asccltalh which of thecells 15 dcficlcllt in which the electrolyte is below its electrode mayin electrolyt by a Process of elimination be ascertained by a process ofelimination as fully The voltage between the electrodes 9 and 10 isdescribed in connection with Fig. 1.

approximately six-tenths of a volt and the voltage In the modificationshown in Fig. 3 the parts across electrodes 10 and 11 is substantiallythe thereof corresponding to like parts in Fig. 1 are 75 same, while thevoltage across the electrodes 9 indicated by the same numerals as thoseof Fig.

left into contact with 1, but have the exponent b added thereto. In thisillustration, the conductor 36 connected with the electrode 9 terminatesin aswitch contact 37, while the conductor 38 connected with theelectrode 10 terminates in a switch contact. 39. The conductor 40connected to the electrode 11 is connected direct to one of the bindingposts of the indicator 27*, while the other side of the indicator isconnected thru a conductor 41 with the single pole switch 42, which isnormally in open position. When it is desired to test the condition ofthe cells the switch 42 is closed with contact 37 thereby closing thecircuit between the electrodes 9 and 11 and if the electrolyte in thecells with which these electrodes are associated is above its normallevel, the needle will deflect. However, if the electrode is below itsnormal level in either of these cells, there will be no indication. Ifupon closing the switch with contact 39 there is an indication, thiswould indicate that the level of the electrolyte with which electrode 9is associated is below its normal value. However, if there is anindication upon closure of the switch with both contacts 37 and 39, thiswould indicate that the level of the electrolyte in all of the cells isabove its normal level. In this modification, there are only twoindications as distinguished from the three indications of Figs. 1 and2.

The modification of the invention illustrated in Fig. 4 is a slightrearrangement of the wiring of Fig. 3 and the parts in this figure,similar to those of Fig. 1, are indicated by like numerals but have theexponent c added thereto. In this modification, the conductor 43connected with the electrode 9 terminates in the switch contact 44 and"thetconductor 46 connected with the electrode 11 terminates in theswitch contact 47. In this illustration, the electrode 10 is connectedby means of the conductor 45 with one side of the indicator 27, whilethe other side of the indicator is connected thru a conductor 48 withthe single pole switch 49 normally in open position. To test thebattery, the switch 48 is turned to the the contact 44 thus closing thecircuit across electrodes 9 and 10 and if the electrolyte in the cellswith which these electrodes are associated is above its predeterminedvalue, the indicator will deflect to one side of its center position.When the switch is turned to the right to connect with the contact 4'7thereby closing the circuit across electrodes 10 and 11, if theelectrolyte in the cells 2 and 3 is above its normal value, the needleof the indicator 2'7! will deflect in the opposite direction from itsfirst indication. This illustration, like Fig. 3, gives only twoindications providing the electrolyte in all of the cells is above its.normal value. If inconnecting the instrument across the electrodes 9 and10 there was no indication, but upon connection of the indicator acrosstheelectrodes 10 and 11 there was an indication, this would indicatethat the electrolyte in cell 1 is below the end of the electrode 9 whileif there was no indication when the instrument is connected across theelectrodes 10 and 11 but an indication across electrodes 9 and 10, thiswould indicate that the electrolyte in cell 3 was below its normal valueand if there were no ind-cations when the switch is connected with boththe contacts 44 and 47, this would indicate that the elecrolyte in cell2, or possibly others, was below its normal level.

In the modification illustrated in Fig. 5, the parts are numbered thesame as in Fig. 1 except that the exponent d is added thereto. In thisillustration, the conductor 50 connected with the electrode 9 terminatesin the switch contact 51, the conductor 52 connected with the electrode10 terminates in the switch contact 53 and the conductor 54 connectedwith the electrode 11 terminates in the switch contact 55. The indicator2'7 is connected to the double pole switch 56 thru conductors 57 and 58and the switch is provided with contact arms 59 and 60 adapted tocooperate wilh the previously mentioned switch contacts when turned orrotated to the right, as viewed in Fig. 5. Upon rotation of the switchto the right into contact with the switch contacts 51 and 53, theinstrument is connected across the electrodes 9 and 10 and if theelectrolyte in the cells with which these electrodes are associated isabove its normal level, the index will be deflected from its normalposition. However, if the electrolyte is below either of the electrodes,there will be no indication. Upon rotation of the switch into contactwith the switch contacts 53 and 55, the instrument 2'7 will be connectedacross the electrodes 10 and 11 and if the electrolyte in the cells withwhich these electrodes are associated is above the normal level, therewill be a deflection of the needle. However, if the electrolyte ineither of these cells is below the end of the electrodes, there will beno deflection of the needle.

In Fig. 6 the electrode is illustrated embodied in the filler capclosure and comprises preferably a carbon contact member 62 secured inand extending thru the usual filler cap 61. This filler cap is usuallyprovided with an air vent for the escape of gases from the various cellsand it is to be understood that this usual vent opening is retained inthe filler cap to provide for the escape of the gases arising from thecells. As illustrated, the contact member 62 extends'thru the cap and isprovided, on its exterior end, with a spring clip 63 to facilitate theconnection of the conductors with the electrode. While this spring clipprovides a convenient way of attaching the conductor to the electrode,it is to be understood that other types of connecting means may beutilized for this purpose. While the electrode is preferably made ofcarbon, it is to be understood that electrodes made of other materialmay be used, the condition being that the material of the electrode mustnot react with the electrolyte to set up any secondary action in thebattery, which would be detrimental to the functioning of the battery.Carbon is preferable since it is inert and not acted upon in any way bythe electrolyte and, therefore, does not introduce any foreign substanceinto the cell of the battery which reacts with the electrolyte. Byplacing the auxiliary electrodes in the cells thru the usual filler capfor the cell, the invention may be applied to, existing batterieswithout any material alterations of the same other than the substitutionof new I filler caps, provided with the electrodes, for the normal caps.Placing of the auxiliary electrodes into the electrolyte is advantageousin that the small currents drawn from the battery do not materiallyaffect the capacity of the battery.

It is to be understood that the invention is not limited by the exactembodiments shown, which are merely by way of illustration and notlimita-l tion as various and other forms of the device will, of course.be apparent to those skilled in the art withoutdeparture from the spiritof the invention or the scope of the claim.

What is claimed is:

In combination with a battery having more than two cells, an auxiliaryelectrode disposed in each cell the lower end of which terminates at apredetermined point below the normal level of the electrolyte, anelectrical indicator, and switching means to connect said indicatorsuccessively across the auxiliary electrode in one end cell and theauxiliary electrode in the cell adjacent thereto, the auxiliaryelectrode in the said

